I have a rechargeable Battery Pack for XT1800. The batteries are "dead" but you could get a Battery Shop to duplicate it. 10 Rechargeable batteries are required to get the same voltage as 8 Alkalines. PM me your address if you would like me to post it to you. When using XT 1800 I used a Garmin GPS 12 (non available now) with no interference issues, interference appears to only be occuring with 5000, 7000 and 2300 machines. Cheers Vivace.

That would be great, I'd love to pull it apart and try use the biggest battery possible out of it. It's 12V I'm pretty sure so making the equivalent in lithium instead of nickel would be lighter, and bigger capacity. I'll PM you now